(1) Field of the Invention
The present invention relates to an electroluminescent light source. In particular, it relates to an electroluminescent filament capable of emitting a plurality of colors and a method and a device for manufacturing the same.
(2) Description of the Related Art
The conventional cable-like light emitting device mainly comprises: Neo light, with fragile glass outer layer, dangerous factors of high voltage and high frequency and incapability of being readily shaped, has the drawbacks of high power consumption and high cost for manufacture and maintenance. The colored incandescent light using filament to emit incandescent light and colored lamp-cover to achieve colored light effect consists of a plurality of small incandescent bulb or light emitting diode (LED); This kind of color tube is of substantial diameter and its diameter of lattice light filament is 10 mm or more, and it is power-consuming, with its freedom of shaping being restricted by the large diameter and rigidity. The further drawbacks of said two devices lie in low efficiency in light emission, proneness to conductive wire damage and likelihood to cause fatal accidents when used in rainy weather.
Still another electroluminescent light source also has its deficiency. For example, the technical solution disclosed in the Patent No. CN1101125C and U.S. Pat. No. 5,869,930 relates to a mono-color light source using solvent to dilute the substance of electrolytic layers, making it loosely organized and producing a lot of blowholes and pores, which should be filled in with transparent substance for continuous light emission. The process is complex, and because transparent filler does not have a long, effective conductivity such that this kind of light source is apt to lose its function, the light emission can not last long, nor can the light be emitted evenly.